Reverse image pantographic apparatus

ABSTRACT

A pantographic apparatus of the type which, by virtue of intermeshing gears bearing styli, simultaneously produces a true and a superposed reverse image of a tracing is described.

Umted States Patent [1 1 11 3,775,852 Sandin Dec. 4, 1973 [54] REVERSE IMAGE PANTOGRAPHIC 548,327 10/ l895 Russell et al. 33/23 F APPARATUS 84l,223 l/l907 Bronner 33/23 E [76] Inventor: Nels T. Sandin, 15 Van Etten Rd., FOREIGN PATENTS OR APPLICATIONS Binghamton, 13905 207,604 311909 Germany 33 23 E {22] Filed: Aug. 14, 1972 Primary Examiner-Harry N. Haroian 280,507 Att0rneyFrederick E. Bartholy [52] US. Cl... 33/23 E [57] ABSTRACT [51] Int. Cl B431 13/10 58 Field of Search 33/23 A Pantographic apparatus of the yp which, y virtue of intermeshing gears bearing styli, simultaneously [56] References Cited produces a true and a superposed reverse image of a UNITED STATES PATENTS "acmg desmbed' 2,588,757 3/1952 Peeples 33/23 C 4 Claims, 2 Drawing Figures REVERSE IMAGE PANTOGRAPHIC APPARATUS This invention relates to the art of drawing and tracing of images and, more particularly, to an apparatus which mechanically produces a true and a reverse image of a tracing or drawing, generally known as a pantograph.

Pantographs of various types are well known and have been described in the prior art. These generally consist of arms having certain interlinkages for the proportional enlargement or reduction in scale of a given drawing.

It is also known in the prior art that linkages of arms may be provided by means of intercoupling gears for the purpose of simultaneously drawing two images, one of which may be the reverse of the other. U. S. Pats. Nos. 548,327 and 841,223 illustrate this principle. Such pantographic devices have the drawback that the reverse image, while an accurate reproduction, is separated from the original tracing and cannot be drawn superposed.

Accordingly, it is the primary object of this invention to provide a pantographic apparatus in which the reverse image is exactly superposed on the tracing of the original, thereby forming a symmetrical reproduction.

It is a further object of this invention to provide a pantographic drawing apparatus, simple in construction, in which a follower arm, separated from the tracing arms, enables the creation of intricate symmetrical designs and patterns appearing as a unitary image.

It is a particular feature of the invention that the component elements of the instrument may be readily assembled or disassembled, making the unit portable and easily placed in operation without the requirement of tools.

Other objects and features will be apparent from the following description of the invention, pointed out in particularity in the appended claims, and taken in connection with the accompanying drawing, in which:

FIG. 1 is a plan view of the pantographic apparatus constructed in accordance with the invention; and

FIG. 2 is a side view thereof, taken along line A-A of FIG. 1.

Referring to the drawing, as seen in FIG. 1, the apparatus consists of base supporting members and 11 which may be parallel bars placed side by side at a suitable distance to support a platen 12. Secured to the supporting members 10 and 11 is a horizontally extending V-block 14 which may be affixed in any suitable manner, as by means of screws 1-5 and 16 shown by way of example in FIG. 2. Other means may also be used, for example, various types of adhesives. Suffice it to say that the block 14, which is preferably of steel, is firmly secured to the support members 10 and 11 to form a solid assembly. It is to be noted that the V-block 14 is, in fact, the race of a ball bearing accommodating several balls 17, one of which is seen in FIG. 2 and others in dotted line in'FIG. l. The purpose of these will be explained later.

.A carriage 20, consisting of a flat elongated member, has a V-block secured to the top portion of the underside thereof and running transverse thereto. This block forms the upper race of the ball bearings. In this manner, the carriage 20 may be moved over the platen 12. As will be seen, this motion effects the tracing of the horizontal components of a design.

Mounted along the center line on the carriage 20 are gear discs 24, 26 and 28, rotatably supported on studs 25, 27 and 29, respectively. The gear discs are so positioned as to intermesh so that if one is rotated, the others will correspondingly be caused to rotate.

Gear disc 24 has a tracing arm attached to the lower portion thereof below the stud 25 and extending laterally to the carriage 20. Similarly, the disc 26 has a tracing arm 31 attached to the upper portion thereof above the stud 27 and extending laterally to the carriage 20. These attachments may conveniently be made by screws as shown.

Each tracing arm 30 and 31 carries at the end thereof a writing stylus 32 and 33, respectively. The styli may take a variety of forms, such as pencils, pens, and other drafting instruments capable of drawing a line when in motion at a given pressure. The points of the styli are so adjusted as to rest on the platen 12 over which the user may place a sheet of paper or any desired sheet material on which a design is to be made.

A follower arm 35 is attached to the bottom gear disc 28 by means of screws 36 and 37. The arm 35 has a slot 38 so that it may be adjusted as to its effective length and, at the end, is provided with an opening 39 to accommodate a pen or pencil 40 (FIG. 2) which is held in the hand of the user in order to create any particular design.

On the top of the carriage 20 is placed a counter balancing weight 41 which may be positioned up and down along the length of a slot 42 in the carriage 20. A retaining bolt 43 enables the securing of the weight 41 in the desired position.

As can be seen from the drawing, the carriage 20 may not only slide across the platen 12 over the ball bearings, but may also pivot in the direction perpendicular to the platen. As a matter of fact, the entire carriage may simply be lifted from the bearings on which it rests. Consequently, the weight 41 has the function of determining the pressure desired to be exerted on the styli 32 and 33. Such pressure depends of course on the particular styli being used. The dotted outline of the weight 41 in FIG. 2 shows the position when the carriage 20 is lifted.

It will be obvious that when the gear discs are in rotary motion due to the angular movement of the follower 35, the discs 24 and 25 rotate in opposite directions so that the arms 30 and 31 either separate or converge upon each other.

In order to assure that the arms 30 and 31 will not interlock or touch each other due to extensive clockwise motion of the arm 35, and adjustable abutment 45 in the form of a set screw is provided to engage the face 46 of the arm 30.

Referring to the operation, the user, having placed a sheet of paper on the platen 12 will insert a tracing device, let us say a pencil, in the opening 39 and execute any desired shape or configuration of a line. Horizontal motion of this pencil over the platen 12 moves the entire carriage and the styli 32 and 33 will draw parallel lines. Any angular movement of the follower causes the gear disc 28 to rotate, thereby also rotating the discs 24 and 26 which position the arms 30 and 31, respectively, to follow the position of the arm 35. In this manner, the arm 30 describes the identical movement of the follower arm 35, whereas the arm 31 describes the opposite movement thereof, creating a reverse image of the tracing executed by the arm 30. Since, by virtue of the mechanical construction, the arms 30 and 31 are so placed as to maintain symmetry of the drawn lines, the

movement of the follower arm 35 will produce a true and a reverse image of the design selected by the operator in exact alignment and symmetrical opposition complimentary to each other. It will be clearly seen that the vertical component of any design is due to the rotary displacement of the discs 24, 26 and 28, whereas the horizontal component is due to the movement of the carriage 20.

A true image of the excursion of the arm 35 is reproduced by the arm 30 and simultaneously an exact reverse image thereof, properly superposed, is executed by the arm 31. All types of intricate and decorative designs may thus be made. It is of course obvious that a template may be laid on the platen 12 which, when followed by the instrument 40 of the arm 35, will be exactly reproduced in a true and a superposed mirror image by the pantographic apparatus herein shown and described. Of course an engraving type stylus may be used in place of the aforementioned writing instruments.

The invention in its broader aspects is not limited to the specific embodiments herein shown and described but changes may be made within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. A pantographic apparatus for the simultaneous presentation of the true and the reverse image of a tracing produced by the excursion of a follower, comprising a platen, a carriage above said platen, a plurality of intermeshing gear discs mounted on said carriage, each of two of said intermeshing gear discs having a tracing arm extending in the direction lateral to said carriage and terminating in a writing stylus, and another of said intermeshing gear discs having a follower extending laterally from said carriage and accommodating a writing instrument, and means for slideably supporting said carriage over said platen, said carriage having an adjustable weight for counterbalancing, thereby determining the effective pressure of said styli upon said platen.

2. Apparatus in accordance with claim 1 wherein said carriage comprises an elongated support mounted on a block forming one race of a ball bearing, the outer race thereof being mounted on a base supporting said platen carries a plurality of balls, whereby said carriage resting solely on said balls may slide across said platen upon horizontal displacement of said follower and may be lifted from said base permitting access to said platen.

3. Apparatus in accordance with claim 1 wherein said intermeshing gears comprise a first outer gear disc, a middle gear disc, and a second outer gear disc, said first gear disc having a tracing arm affixed to the lower portion thereof, said middle gear disc having a tracing arm affixed to the upper portion thereof, and said second outer gear disc having a follower arm affixed to the lower portion thereof by retaining means, permitting the adjustment of said follower as to the effective length thereof.

4. Apparatus in accordance with claim 1 wherein one of said tracing arms has an adjustable abutment for engaging the other of said anns, insuring minimum sepa ration between said arms. 

1. A pantographic apparatus for the simultaneous presentation of the true and the reverse image of a tracing produced by the excursion of a follower, comprising a platen, a carriage above said platen, a plurality of intermeshing gear discs mounted on said carriage, each of two of said intermeshing gear discs having a tracing arm extending in the direction lateral to said carriage and terminating in a writing stylus, and another of said intermeshing gear discs having a follower extending laterally from said carriage and accommodating a writing instrument, and means for slideably supporting said carriage over said platen, said carriage having an adjustable weight for counterbalancing, thereby determining the effective pressure of said styli upon said platen.
 2. Apparatus in accordance with claim 1 wherein said carriage comprises an elongated support mounted on a block forming one race of a ball bearing, the outer race thereof being mounted on a base supporting said platen carries a plurality of balls, whereby said carriage resting solely on said balls may slide across said platen upon horizontal displacement of said follower and may be lifted from said base permitting access to said platen.
 3. Apparatus in accordance with claim 1 wherein said intermeshing gears comprise a first outer gear disc, a middle gear disc, and a second outer gear disc, said first gear disc having a tracing arm affixed to the lower portion thereof, said middle gear disc having a tracing arm affixed to the upper portion thereof, and said second outer gear disc having a follower arm affixed to the lower portion thereof by retaining means, permitting the adjustment of said follower as to the effective length thereof.
 4. Apparatus in accordance with claim 1 wherein one of said tracing arms has an adjustable abutment for engaging the other of said arms, insuring minimum separation between said arms. 